When two people have a need to communicate the exchange of information and/or ideas, it is often useful that they do so in a face to face meeting in which they may simultaneously view and discuss particular documents or tangible objects of interest. Oftentimes, however, such a face to face meeting is impractical as the two or-more people desiring to meet are often located in different cities, opposite sides of the same city, or even separate buildings in a large office complex. The time and expense required for travel often makes it impractical and inconvenient to bring all involved parties together in one location. Furthermore, it may be necessary for all parties to meet for only a short time making it even less practical to bring all interested parties together. In such a situation, it is often useful to take advantage of the technology enabling video teleconferencing (to be referred to herein as teleconferencing) of all involved parties.
If two parties are to participate in a teleconference, each conferee will have placed at their local site a video camera to capture images at their local site, a TV monitor to display video images from a remote site, a microphone to capture the local audio portion of a teleconference site, and a speaker to broadcast the audio portion originating from a remote teleconference site. The result is that a conferee at a local site may view the conferee at the remote site, while at the same time the conferee at the remote site may view the conferee at the local site. The audio portion of the teleconference will be transmitted by the microphone and speaker components. While the above system is described for two teleconference sites, greater than two teleconference sites may be accommodated by providing at each site one monitor, for every teleconference site along with one loud speaker, and one microphone. A conferee would be able to view each and every other conferee.
One utilization of such a teleconference system is that should a local conferee wish to display to the other teleconference sites a particular drawing or diagram, the conferee would put that drawing or diagram in front of the camera for display to other sites, and in some systems would be able to refer to specific items within that drawing or diagram. However, one disadvantage of present teleconference systems is that the other conferees are unable to specifically point at or place markings on particular objects within that drawing or diagram. They are limited to merely verbally describing the object to which they wish to refer within a drawing or diagram. Thus, current methods of video teleconferencing fail to disclose any apparatus by which any of the remote conferees may point at or mark specific items within a remote drawing or diagram.
Several attempts have been made at enabling conferees to point simultaneously to a drawing or diagram which is being viewed by each of the other conferees. While they will be described herein, it should be noted initially that each of the below described systems typically approach the problem using computer imaging as compared to actual images captured by video cameras. One such attempt at enabling conferees to simultaneously point within a drawing employs writing surfaces, such as wall mounted white boards or similar systems that include a translucent screen on which a local conferee may write and on which remote video images are projected from behind. A video camera is placed on the back side of a translucent screen to capture any makings or shadows falling upon the screen. Similarly obtained images from the other teleconference sites are then combined with the local image to form a composite image projected onto the backside of each of teleconference screen. This system is defined as a whiteboard system. Such a system requires proper ambient lighting in order to provide a limited three dimensional view of the user. The system does allow users at remote sites to simultaneously refer to specific items appearing on the translucent screen; however, these images are merely monochrome shadows on a translucent screen and, at best provide a limited degree of three dimensional perspective on the translucent screen. None of the inherent advantages of video teleconferencing are present using a whiteboard system. No color presentation may be made and only very limited three dimensional imaging may occur. Furthermore, a sufficient ambient light condition is required at each teleconference site in order to properly backlight the whiteboard user.
A second approach employed in the prior art is to use a shared workspace to overlay digitized video images on a computer screen. The shared workspace is implemented by devoting a computer screen to the process of producing multiple windows and/or overlaying of images obtained from a varied combination of possible sources including computer simulations and digitized signals from devices such as video cameras, scanners, and visualizers. Each user participating in the shared workspace may simultaneously and individually use the computer cursor to point to specific objects within the shared computer screen workspace. Its applications include (1) joint editing of word processing files or spreadsheets so as to enable users at different locations to work on the same material jointly; (2) overlaying of video scenes with simulated images as in many military aircraft weapons and guidance systems; and (3) overlaying of computer generated and video images for comparing and preparing sketches, animations, and designs. The computer overlay concept may also be simplified so that one user may display their individual image in each and every of the shared workspaces so that each of the users may simultaneously point to objects within the shared workspace.
There are several limitations in the shared computer workspace system. First, the quality of the overlaid image is neither sharp nor stable enough to support sharing detailed documents. Also, digitizing and overlaying of the shared images in competing technology is much more complex and costly than when using simple video technology components in the manner specified in this application. Therefore, a drawing, diagram, or picture which exhibits detail that a user wishes to discuss may not appear clearly enough within the screen image to do so. Second, when three or more users are sharing a workspace, the overlapped image becomes crowded and confused, and identifying the owners of objects within a shared workspace becomes difficult. Identification may be improved by dimming the overlay signal electronically; however, this leads to a degradation of the picture quality. Finally, when a displayed image in the shared workspace is scrolled or moved, the spacial relationship between the overlaid layers is destroyed. Thus, a number of significant advantages of using a video signal are lost in the shared workspace concept.
In other applications, such as sportscasting, it is common to take a recorded video signal and replay it while mixing an overlay of a pointer and/or a marker. Such an application demonstrates the value of pointing and marking within video images, but this stand-alone technology does not reveal how to enable two-way pointing and/or marking at both sites in a video teleconference system. An example of such a teleinteractive system might be returning a video signal with a pointer and/or marker overlaid to point at and show NASA astronauts which button to push on their console in reply to a question. After using and experiencing this simple but useful new function, the user will envision any number of useful applications and will want this functionality at any teleconference site.
Furthermore, video teleconference systems are often provided in a number of applications as turnkey systems comprising a self-contained unit resident at a site. The turnkey systems generally include one or a number of monitors, one or a number of video imaging devices (such as video cameras or video recorders), sound recording componentry, optional compression and decompression circuitry, and data transmission components for sending and receiving a video signal. However, none of the above described turnkey systems enable a user to remotely point and/or mark within a video signal originating at a remote location.
Therefore, it is an object of this invention to provide a system and method for video teleconferencing in which any conferee may point at and/or mark within any other video image, whether local or remote. It is a further object of this invention that any number of conferees individually and simultaneously may point within any video teleconference image. It is yet a further object of this invention to provide a very simple and low cost method to implement this basic, useful function within teleconference systems.